Nissan Altima L32. Manual - part 255

TROUBLE DIAGNOSIS - SPECIFICATION VALUE

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2. Disconnect ECM harness connector. Check pin terminal and connector for damage, and then reconnect it.

>> GO TO 16.

16.

CHECK “A/F ALPHA-B1”

1. Start engine.

2. Select “A/F ALPHA-B1” in “SPEC” of “DATA MONITOR” mode, and make sure that the indication is within

the SP value.

Is the measurement value within the SP value?

YES

>> INSPECTION END

NO

>> Detect malfunctioning part according to 

EC-539, "Symptom Table"

.

17.

CHECK “B/FUEL SCHDL”

Select “B/FUEL SCHDL” in “SPEC” of “DATA MONITOR” mode, and make sure that the indication is within the

SP value.
Is the measurement value within the SP value?

YES

>> INSPECTION END

NO-1 >> More than the SP value: GO TO 18.

NO-2 >> Less than the SP value: GO TO 25.

18.

DETECT MALFUNCTIONING PART

1. Check for the cause of large engine friction. Refer to the following.

-

Engine oil level is too high

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Engine oil viscosity

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Belt tension of power steering, alternator, A/C compressor, etc. is excessive

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Noise from engine

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Noise from transmission, etc.

2. Check for the cause of insufficient combustion. Refer to the following.

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Valve clearance malfunction

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Intake valve timing control function malfunction

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Camshaft sprocket installation malfunction, etc.

>> Repair or replace malfunctioning part, and then GO TO 30.

19.

CHECK INTAKE SYSTEM

Check for the cause of uneven air flow through mass air flow sensor. Refer to the following.

• Crushed air ducts

• Malfunctioning seal of air cleaner element

• Uneven dirt of air cleaner element

• Improper specification of intake air system
Is the inspection result normal?

YES

>> GO TO 21.

NO

>> Repair or replace malfunctioning part, and then GO TO 20.

20.

CHECK “A/F ALPHA-B1”, AND “B/FUEL SCHDL”

Select “A/F ALPHA-B1” and “B/FUEL SCHDL” in “SPEC” of “DATA MONITOR” mode, and make sure that the

each indication is within the SP value.
Is the measurement value within the SP value?

YES

>> INSPECTION END

NO

>> “B/FUEL SCHDL” is more, “A/F ALPHA-B1” is less than the SP value: GO TO 21.

21.

DISCONNECT AND RECONNECT MASS AIR FLOW SENSOR HARNESS CONNECTOR

1. Stop the engine.

2. Disconnect mass air flow sensor harness connector. Check pin terminal and connector for damage and

then reconnect it again.

>> GO TO 22.

EC-142

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TROUBLE DIAGNOSIS - SPECIFICATION VALUE

22.

CHECK “A/F ALPHA-B1”

1. Start engine.

2. Select “A/F ALPHA-B1” in “SPEC” of “DATA MONITOR” mode, and make sure that the indication is within

the SP value.

Is the measurement value within the SP value?

YES

>> Detect malfunctioning part of mass air flow sensor circuit and repair it. Refer to 

EC-168, "DTC

Logic"

. Then GO TO 29.

NO

>> GO TO 23.

23.

CHECK “MAS A/F SE-B1”

Select “MAS A/F SE-B1” in “SPEC” of “DATA MONITOR” mode, and make sure that the indication is within the

SP value.
Is the measurement value within the SP value?

YES

>> GO TO 24.

NO

>> More than the SP value: Replace mass air flow sensor, and then GO TO 29.

24.

REPLACE ECM

1. Replace ECM.

2. Go to 

EC-27, "ADDITIONAL SERVICE WHEN REPLACING CONTROL UNIT : Special Repair Require-

ment"

.

>> GO TO 29.

25.

CHECK INTAKE SYSTEM

Check for the cause of uneven air flow through mass air flow sensor. Refer to the following.

• Crushed air ducts

• Malfunctioning seal of air cleaner element

• Uneven dirt of air cleaner element

• Improper specification of intake air system
Is the inspection result normal?

YES

>> GO TO 27.

NO

>> Repair or replace malfunctioning part, and then GO TO 26.

26.

CHECK “B/FUEL SCHDL”

Select “B/FUEL SCHDL” in “SPEC” of “DATA MONITOR” mode, and make sure that the indication is within the

SP value.
Is the measurement value within the SP value?

YES

>> INSPECTION END

NO

>> Less than the SP value: GO TO 27.

27.

CHECK “MAS A/F SE-B1”

Select “MAS A/F SE-B1” in “SPEC” of “DATA MONITOR” mode, and make sure that the indication is within the

SP value.
Is the measurement value within the SP value?

YES

>> GO TO 28.

NO

>> Less than the SP value: Replace mass air flow sensor, and then GO TO 30.

28.

CHECK INTAKE SYSTEM

Check for the cause of air leak after the mass air flow sensor. Refer to the following.

• Disconnection, looseness, and cracks in air duct

• Looseness of oil filler cap

• Disconnection of oil level gauge

• Open stuck, breakage, hose disconnection, or cracks of PCV valve

• Disconnection or cracks of EVAP purge hose, open stuck of EVAP canister purge volume control solenoid

valve

• Malfunctioning seal of rocker cover gasket

• Disconnection, looseness, or cracks of hoses, such as vacuum hose, connecting to intake air system parts

TROUBLE DIAGNOSIS - SPECIFICATION VALUE

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• Malfunctioning seal of intake air system, etc.

>> GO TO 30.

29.

CHECK “A/F ALPHA-B1” AND “B/FUEL SCHDL”

Select “A/F ALPHA-B1” and “B/FUEL SCHDL” in “SPEC” of “DATA MONITOR” mode, and make sure that the

indication is within the SP value. 
Is the measurement value within the SP value?

YES

>> INSPECTION END

NO

>> Detect malfunctioning part according to 

EC-539, "Symptom Table"

.

30.

CHECK “B/FUEL SCHDL”

Select “B/FUEL SCHDL” in “SPEC” of “DATA MONITOR” mode, and then make sure that the indication is

within the SP value.
Is the measurement value within the SP value?

YES

>> INSPECTION END

NO

>> Detect malfunctioning part according to 

EC-539, "Symptom Table"

.

EC-144

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POWER SUPPLY AND GROUND CIRCUIT

POWER SUPPLY AND GROUND CIRCUIT

Diagnosis Procedure

INFOID:0000000004349186

1.

INSPECTION START

Start engine.
Is engine running?

YES

>> GO TO 8.

NO

>> GO TO 2.

2.

CHECK ECM POWER SUPPLY CIRCUIT-I

1. Turn ignition switch OFF and then ON.

2. Check the voltage between ECM harness connector and

ground.

Is the inspection result normal?

YES

>> GO TO 4.

NO

>> GO TO 3.

3.

DETECT MALFUNCTIONING PART

Check the following.

• IPDM E/R harness connector E18

• 10A fuse (No. 35)

• Harness for open or short between ECM and fuse

>> Repair open circuit or short to ground or short to power in harness or connectors.

4.

CHECK GROUND CONNECTION-I

1. Turn ignition switch OFF.

2. Check ground connection E9. Refer to Ground Inspection in 

GI-45, "Circuit Inspection"

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Is the inspection result normal?

YES

>> GO TO 5.

NO

>> Repair or replace ground connection.

5.

CHECK ECM GROUND CIRCUIT FOR OPEN AND SHORT-I

1. Disconnect ECM harness connectors.

2. Check the continuity between ECM harness connector and ground.

3. Also check harness for short to power.
Is the inspection result normal?

YES

>> GO TO 7.

ECM

Ground

Voltage

Connector

Terminal

E10

93

Ground

Battery voltage

PBIA9561J

ECM

Ground

Continuity

Connector

Terminal

F14

12

Ground

Existed

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E10

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